"is.na() applied to non-(list or vector) of type 'language'" when passing a Julia's boolean variable to R's smooth.spline about rcall.jl HOT 2 OPEN

Can you try using the most recent version of RCall (0.13.17)? I don't get an error message with RCall 0.13.17 and R 4.2. I'm guessing it's easier to upgrade RCall than R and the relevant part of the R printing source hasn't changed:

    if (!is.na(cv <- x$cv)) 
        cat(if (cv) 
            "PRESS(l.o.o. CV): "
        else "GCV: ", format(x$cv.crit, digits = digits), "\n", 
            sep = "")

from rcall.jl.

I tried

• Julia 1.9.1 + RCall 0.13.17 (R 3.6.3)
• Julia 1.8.2 + RCall 0.13.16 (R 4.1.0)

Both throw the same error message

from rcall.jl.